Seasonal Cycles

The earth's atmosphere is about 430 miles thick. Without this layer of gases to protect us, we could not live. We would be scorched by the sun during the day and frozen at night. Most of the atmosphere is a thin mix of gases that is calm and unchanging. But the lowest 7 miles--the layer in which we live and breathe--contains all the weather we experience, and is thick with gases, water, and dust. As the sun warms the land and sea beneath it, the heat keeps this lower 7 miles swirling and churning. It is the constant swirling of this lowest layer, called the troposphere, that gives us everything we call weather--from the gentle showers to raging hurricanes and tornadoes. 

The earth has a clear pattern of wind circulation that results from the effect of the earth's rotation and the way that the heat of the sun is distributed. It has become easier to view these cycles and patterns because of photos that can now be taken from satellites orbiting the earth. These global patterns cause weather to occur in cycles--the typhoons that are generated from the China Sea and affect southeast Asia--the hurricanes that begin in the Caribbean and affect the southeastern United States and Central America--the tornadoes that travel through the American midwest.

Sample some of the following activities to learn more about seasonal cycles of the earth.


Places To Go    People To See    Things To Do    Teacher Resources    Bibliography

Places To Go

The following are places to go (some real and some virtual) to find out about seasonal cycles of the earth.

Biomes of the World
Explore a temperate deciduous forest. This particular biome exhibits all 4 of earth's seasons. Find out how the animals of this biome adapt to its seasonal changes.
Globe Program
Visit schools around the United States as they participate in the Globe program. Globe is a worldwide network of students, teachers, and scientists working together to study and understand the global environment.
National Weather Service
The National Weather Service is THE place to go to find out about weather and its cycles.
Nova Online: Flood!
Visit a floodplain. The seasonal cycle of rivers flooding is a normal part of nature and is part of the way that fertile soil builds itself up. In fact, the ancient Egyptians used to refer to the annual flooding of the Nile as the "gift of the Nile" and they welcomed the benefits that it brought. In modern times, problems arise when humans build cities and homes in floodplains and try to rechannel rivers to avoid flooding.
USA Today Weather Highs
Check out states' highest recorded temperatures. Check out state's lowest recorded temperature. Here's a handy temperature calculator if you need to convert between Fahrenheit and Celsius.
World Temperature Extremes
Travel to the hottest and coldest places on the planet. You may not recognize the place where the lowest temperature ever recorded in Utah occurred. Use the Utah Collections Multimedia Encyclopedia and find out what county this place is in.

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People To See

April 10, 1815: Tambora Explosion Triggers 'Volcanic Winter'
In 1815 the Tambora volcano erupted in Indonesia, spewing enormous amounts of particles into the atmosphere. The following year, areas in Europe and North America had temperatures that were far below normal. Scientists, therefore, call 1816 “the year without a summer”. This cold summer caused crop failures and food shortages.
The Deadliest Tsunami in History?
Spend time with the resilient people of Indonesia, who survived the devastating Indian Ocean tsunami in 2004.
Exploring the Sun Through Ancient Civilizations
Many of monuments they left behind were designed to celebrate the longest and shortest days of the year. Places such as Stonehenge in England and Hovenweep in southern Utah were aligned to catch the rays of the sun in specific places on the longest and shortest days of the year.
Google Earth
The seasons of the earth are a result of the tilt of the earth and its rotation around the sun. So depending on the time of the year, either the northern hemisphere or the southern hemisphere is tilted so that it receives more of the sun’s rays which results in summer. With a visual representation of the earth, it's easy to learn about the earth’s seasons.
How Floods Work
See worldwide communities that are affected by flooding. Floods are the most destructive of natural forces caused by seasonal cycles. They cause more loss of life and damage more property than any other natural disaster.
How Hibernation Works
Visit bears in their dens, chipmunks in their nests, and badgers in their burrows. These animals adapt to the seasonal cycles of the earth by hibernating during the coldest times of the year.
Hurricane Hunters
Visit with some real hurricane hunters. These Air Force men and women fly airplanes right into the eye of hurricanes to gather data.
Hurricane Mitch
Meet Hurricane Mitch. He was one the most destructive hurricane in recorded history. He devastated Honduras in 1998. More than 35 inches of rain fell on Honduras over the course of 5 days which caused massive floods and mudslides and killed over 11,000 people.
Talk with stormchasers. They are men and women who are passionate about seasonal weather cycles. Their job is to observe and document severe weather.
Who is Jack Frost?
Get to know Jack Frost. He is associated with the seasonal cycles of winter. Jack Frost was originally part of Norse legend and was called Jokul Frosti which means icicle frost. He was the son of the god, Kari.
Yellow River
This river has flooded so many times and has damaged so much farmland and killed so many people that it is sometimes called “China’s Sorrow”. Its collective floods have killed more people than any other natural disaster. In 1931 alone, a flood of the Yellow River killed almost 4 million people.

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Things To Do

A Paleo Perspective on Global Warming
Study climate of the past. It can help us understand earth's climate of today as well as that of the future.  
All About Glaciers
Find out about the forces that make glaciers.
Climate Prediction Center
Check out global climate highlights and anomalies. Sometimes weather cycles go awry.  
Weather all over the world is affected by ocean currents. Find out more.
El Niño
El Niño is a weather condition where a warm ocean current that is normally situated off Australia's coast moves east toward the coasts of Equador and Peru. La Niña is kind of like the opposite of El Niño. Its cycle involves strong trade winds and cooler Pacific waters. From NOAA, check out these FAQs about El Niño and La Niña.
Enchanted Learning: The Seasons and Axis Tilt
Find out the difference between a solstice and an equinox.
Greenhouse Effect
The greenhouse effect is an increase in the temperature of a planet as heat energy from sunlight is trapped by the gaseous atmosphere. Check out this chart of the greenhouse effect and this one.
Mr. Dowling's Season's Page
The tilt of the earth is 23 ½ degrees. Discover what this has to do with the seasonal cycles of the earth.
The Old Farmer's Almanac
Virtually thumb through the old Farmer's Almanac. It has been around since 1792! It has everything you ever wanted to know about planting cycles, weather cycles, and more.  
Create a seasonal postcard.
Science U: Seasons Reasons
Find out what would happen to our seasons if the tilt of the earth's axis was 0°. (Hint: You would never need your woolen mittens or Bermuda shorts).
Seasons of the Year
Find out if seasons exist at the equator.
Space Weather Today
Check out the current weather on the sun.
Find out what the weather cycles are that produce tornadoes more often at certain times of the year.
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Teacher Resources

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  • Frandon, John. How the Earth Works. Reader's Digest: Pleasantville, New York, 1992.
  • Farndon, John. Weather. New York: DK Pub., 1998.
  • Kahl, Jonathan D.Weather Watch: Forecasting the Weather: Minneapolis : Lerner Publications, c1996.
  • Kerrod, Robin. Weather. New York: Lorenz Books, 1997.
  • Llamas Ruiz, Andres. Seasons. New York: Sterling Pub., 1996.
  • Llewellyn, Claire. Wild Wet and Windy. Cambridge, Mass.: Candlewick Press, 1997.
  • Malam, John. Wacky Weather. New York: Simon & Schuster Books for Young Readers, 1998.